You are all too young to remember, but this was actually a feature in Warband Beta once. Sadly it caused a bug/glitch which the devs could not fix, so they took it out again.
FSE can't really change that, cRPG team on the other hand are sort of hacking into Warband and editing stuff, which enables them to do more things and seemingly they were able to add it without trouble (unlike Taleworlds).